<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style lang="log">
        .box{
            width: 300px;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            height: 300px;
            background-color: antiquewhite;
        }
       :hover.box{
        width: 260px;
        height: 260px;
        background-color: aqua;
        border: 20px solid red;
       
       }
 
    </style>
</head>
<body>
    <div class="box">
        <h3>鼠标进入样式改变</h3>
        <h3>我叫王文杰</h3>
    </div>
</body>
</html>